Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.72: Poster

Tuesday, March 15, 2011, 18:00–21:00, P3

Contact degradation in wet-chemically produced high mobility semiconductor devices — •Mark Nikolka, Marlis Ortel, and Veit Wagner — School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany

Novel wet chemical processing techniques have recently enabled to produce very high mobility devices, e.g. diodes or field-effect transistors (FETs). Yet, for high mobility devices effects start playing a role which previously could be neglected. One of these effects is contact degradation due to high current densities which eventually renders the device useless.

Therefore, a study was done on high mobility (µ > 1 cm²/Vs) FETs made from a metal oxide-based semiconductor with gold as electrode material. The investigated devices had wide electrodes with a typical cross sectional area of 20 um x 30 nm, i.e. the electrodes were wider than the channel length of the transistor. Nevertheless these devices showed strong effects of contact degradation even after recording a single electrical device characteristic lasting less than 60 seconds. Those effects hence, could be related to high current densities present in the FET electrode finger structure. Furthermore, it was found that different types of damages occurred at the source and the drain contact, respectively. This difference cannot be explained by simple electromigration just in the elctrodes but has to be correlated to the transistor channel as well. A corresponding, more complex model is presented which explains the experimental findings.